Atom with electrons

Developing the Atomic Theory

  • 300


    Aristotle believed in four elements, air, water, fire and earth. he believed that no matter how many times you cut something in half, you still get a smaller peice of that matter.
  • 300

    Arostotle's Atomic Model

    Arostotle's Atomic Model
  • 400


    Around 400 B.C.E, a scientist named Democritus believed that if you keep cutting something in half it becomes an atom. He proposed that these tiny particales called atoms, make up all matter everywhere.
  • 400

    Democritus's model

    Democritus's model
  • John Dalton

    John Dalton
    In 1803 scientist John Dalton reintroduces the concept of atoms that Democritus made with with actual evidence to support his claims and ideas.
  • Dalton's Atomic Model

    Dalton's Atomic Model
  • J.J Thomson

    J.J Thomson
    In a 1897, J.J Thomson he identified particles that are present in every single atom.
  • Thomson's Atomic Model

    Thomson's Atomic Model
  • Millikan's Atomic Model

    Millikan's Atomic Model
  • Robert Millikan

    Robert Millikan
    In 1909 Robert Millikan determined the unit charge of the electron.
  • Ernest Rutherford

    Ernest Rutherford
    In 1911 Ernest Rutherford discovered the positivley charged nucleus of an atom.
  • Rutherford's Atomic Model

    Rutherford's Atomic Model
  • Neils Bohr

    Neils Bohr
    Neils Bohr discovered in 1913 that electrons move about the nucleus in paths.
  • Bohr's Atomic Model

    Bohr's Atomic Model
  • James Chadwick

    James Chadwick
    James Chadwick discovered the neutron in 1932.
  • Chadwick's Atomic Model

    Chadwick's Atomic Model